1. Field of the Invention
The present invention relates to a mobile communication terminal, base station and registration control method.
2. Description of the Related Art
With the proliferation of mobile telephones and increasing high performance, expectations are increasing to provide a wireless multicast service. Several specific methods have been proposed to provide a multicast service using mobile telephones.
A description is given hereafter of a general method for a mobile communication terminal to receive program broadcasts by a multicast service from a wireless base station. A wireless base station broadcasts programs using a specific frequency channel F. A mobile communication terminal assigned frequency channel F for communications with a wireless base station can receive program signals and receive programs by decoding program signals through a decryption means.
However, a mobile communication terminal assigned a frequency channel outside frequency channel F for communications with a wireless base station is unable to receive the program signals. A mobile communication terminal must undergo processing, called registration, with the wireless base station thereby changing the assigned frequency channel to F in order to receive the program signals. In this way, even a mobile communication terminal that has a different original frequency channel can receive program signals thereby enabling reception of a program by decoding the program signals through a decryption means. When completing the reception of the program, the corresponding mobile communication terminal can change the frequency channel back to the frequency channel prior to receiving the program by once again undergoing registration.
Meanwhile, technology has been proposed (reference is made, for example, to Japanese Laid Open Patent Publication 2002-281152) for preemptively preventing congestion when viewers/listeners attempt to connect at the same time to a specific connection address designated by the broadcast station for an audience to participate in a television or radio program.
However, with the technology disclosed in the above document, no consideration is given to a concentration of registrations to a frequency channel for wireless base stations when offering a wireless multicast service. For example, there is the problem that even if registrations are concentrated to a specific frequency channel for a wireless base station when a certain program is multicast from a wireless base station at the time of completing the program, there is no method to avoid congestion of the frequency channel where registrations have concentrated for each wireless base station.